I was thiking of things like setting up alternative pets incase your pet dies and you cant ress it yet becase its on cooldown
Showing some more infoamtion about the enemy's his pets
Overvieuw at the end of a battle of what damage taken / done like pvp overview screen
A popup to keep or release a pet after capturing it, (noone wants poor pets anyway)
Better overvieuw on the pet info interface, better grouping of pets whit same name (type)

those are things i came up whit to make an awsome pokemon addon but i was wondering if anyone else had any plans to make for the pokemon games or is working on something awsome

for now there is http://wow.curseforge.com/addons/pokemon-trainer/ which is about to put info in the tooltip of wild pets wether your current team has an advantage on that type or not as well as list the enemies abilities that he could use.
I guess there is still room for improvement and new features

Music (if possible), i want the pokemon battle music!
Not sure if it is possible to replace music in wow (legally) and the battle music is probebly copyrighted.
But you could make it so that the user has to add his 'own' music to a folder.